In time, they met Tenb Mumn, a Sullustan Rebel Alliance recruiter. He promised them a quick and easy Psych program with the Alliance, as well as plenty of adventure and excitement. They signed right up and were shipped back to Sullust.
There, Jan Dodonna broke the news that there was absolutely no psych program, but they were always in need of pilots.
Klivian eventually was drafted into Rogue Squadron by Luke Skywalker, the guy who basically got his friend Biggs killed at the Battle Of Yavin. Klivian fought in the Battle Of Hoth alongside Skywalker, and managed to take out the lead AT-AT by crashing his damaged Snowspeeder into the cockpit. Derek and his gunner, Kesin Ommis, ejected in time to survive and somehow make it back to the evacuation staging area before Luke did.